WO2018184273A1 - Iron-based amorphous alloy and preparation method therefor - Google Patents

Abstract

An iron-based amorphous alloy as represented by formula (I), FeaBbSic (I), in which a, b, and c respectively represent the atomic percentage of the corresponding components, 80.0 ≤ a ≤ 82.0, 11.0 ≤ b ≤ 13.0, 6.5 < c ≤ 8.0, and a + b + c = 100, the saturation magnetic induction thereof not being less than 1.60 T. And a preparation method for the iron-based amorphous alloy.

Description

Iron-based amorphous alloy and preparation method thereof

This application claims the priority of the Chinese Patent Application filed on Apr. 6, 2017, the Chinese Patent Office, Application No. 201710221247.X, entitled "An Iron-Based Amorphous Alloy and Its Preparation Method", the entire contents of which are hereby incorporated by reference. The citations are incorporated herein by reference.

Technical field

The invention relates to the technical field of amorphous alloys, in particular to an iron-based amorphous alloy and a preparation method thereof.

Background technique

Due to its low iron loss, high saturation magnetic flux density, high magnetic permeability and other advantages, Fe-based amorphous alloy ribbons such as Fe-Si-B amorphous alloy ribbons are widely used as cores for power transformers and high frequency transformers. Based on the above characteristics, amorphous iron-based materials have dominated the field of transformers for a long time.

With the continuous renewal of silicon steel materials, the advantages of amorphous materials are relatively weak. For example, the saturation magnetic density of amorphous materials is significantly lower, and with the upgrading of silicon steel sheet rolling equipment and processes, silicon steel sheet materials have been thinning trend and performance is gradually decreasing; amorphous materials are improving magnetic density and reducing A lot of work has been done on the loss side, but from the viewpoint of the performance of the amorphous product in the market, there has been no amorphous material with low loss performance and high saturation magnetic density.

For example, in improving the saturation magnetic flux density, Publication No. No. Hei 6-220592 Japanese Patent discloses a composition of an amorphous alloy ribbon by the formula _{Fe a Co b Si c B d} M x represented by its atomic percent The components are: 60 ≤ a ≤ 83, 3 ≤ b ≤ 20, 80 ≤ a + b ≤ 86, 1 ≤ c ≤ 10, 11 ≤ d ≤ 16; when M is Sn, 0.1 ≤ x ≤ 1.0; when M is When Cu is 0.1 ≤ x ≤ 2.0; when M is S, 0.01 ≤ x ≤ 0.07; a + b + c + d + x = 100. The above scheme has a large saturation magnetic flux density due to the addition of Co; however, Co is a very expensive element, although a Co-containing iron-based amorphous alloy ribbon can be used in some places where high quality is required, but the cost is still high. The inadequacies of the technology.

The publication No. CN1124362C discloses an iron-based amorphous alloy ribbon which can maintain a high magnetic flux density even in the case of high iron content, and the temperature difference condition exists between different portions of the core even during annealing. Underneath, it can still be made into a core with good soft magnetic properties; its main components contain Fe, Si, B, C and P elements and unavoidable impurities, and its composition is in atomic percentage: 82<Fe≤90, 2≤ Si<4,5<B≤16, 0.02≤C≤4, 0.2≤P≤12, and the Bs value after annealing is 1.74T. However, on the one hand, the addition of P element is large, combined with the actual situation of the domestic and international ferrophosphorus industry, the preparation conditions of ferrophosphorus are relatively extensive, the impurity content is too high, and the use condition of amorphous alloy cannot be achieved. In the process of using a large amount of conventional conditions, the ferro-phosphorus can cause crystallization and brittleness of the strip; on the other hand, the heat treatment process of the strip prepared by the phosphorus-containing alloy is easily oxidized, and the apparent quality and performance of the strip surface after heat treatment are poor. . If such alloy composition is used for industrial production, it is necessary to add the step of phosphorus iron refining and the anti-oxidation process of the annealing process, which not only increases the complexity of the process, but also needs to improve the current smelting level, which makes the industrial production more difficult.

The Chinese patent publication No. CN100549205C mentions that the amount of CO or CO ₂ gas blown onto the surface of the copper roll and the Si/C weight ratio are appropriately controlled to form a C concentration distribution measured radially on both surfaces of the alloy strip to the inside thereof. It has a C segregation layer peak in the range of 2 to 20 nm in depth, and effectively solves the problem of embrittlement, surface crystallization and square ratio decrease caused by increasing saturation magnetic flux density Bs in the Fe-based amorphous alloy ribbon; Fe _a Si _b B _c C _d and unavoidable impurities, in atomic percentage, wherein a is 76 to 83.5%, b is 12% or less, c is 8 to 18%, and d is 0.01 to 3%; The invention does not specifically mention the CO or CO ₂ addition process and the control means for controlling the thickness of the segregation layer, and the surface carbon segregation layer has a strict requirements on the preparation range of the surface carbon segregation layer; If the surface roughness is large, the thickness of the oxide layer is not uniform, resulting in uneven depth and range of the C-segregation layer, which makes the stress relaxation uneven, and partially produces a fragile portion because the surface is thick. C- and reduced thermal conductivity of the segregation layer, the surface crystallization is accelerated. The above problems make the preparation process complicated and difficult to control.

Japanese Patent Publication No. Hei 7-33139 discloses a thin strip material having improved iron loss performance and non-brittle cracking, and the patent publication discloses that an amorphous thin strip has excellent magnetic properties and brittleness resistance. The average roughness Ra of the material is 0.6 μm to 0.6 μm below the center line, and the composition expression is Fe _x B _y Si _z Mn _a , 75 _{≤ x ≤} 82, 7 _{≤ y ≤ 15, 7} ≤ _z ≤ 17 in atomic percentage. 0.2 ≤ a ≤ 0.5; although Mn is effective for improving iron loss, increasing its content reduces the magnetic flux density and makes the material brittle.

US Patent No. US8968490B2 mentions that the amorphous alloy melt needs to ensure that its surface tension is greater than 1.1 N/m, which is lower than the surface tension of the strip surface and tends to cause surface protrusions, thereby affecting the strip encapsulation factor; It is also mentioned in the U.S. Patent No. 8,896,489 B2 that a surface tension of less than 1.1 N/m is liable to cause surface defects such as scratches and bright lines on the surface of the strip. The alloys described in the above two patents have _a composition represented by Fe _a Si _b B _c C _d in terms of atomic percentage, wherein 80.5% ≤ a ≤ 83%, 0.5% ≤ b ≤ 6%, and 12% ≤ c ≤ 16.5 %, 0.01% ≤ d ≤ 1%, the strip has a saturation magnetic induction of more than 1.60 T, and exhibits a core loss of less than 0.14 W/kg when measured at 60 Hz and 1.3 T induction level. However, the description of the control of the surface tension of the melt is not specific, and the control of the surface tension of the melt is difficult to be 1.1 N/m or more, and the control of the defects and the difficulty of the tape going forward are increased.

From the above background information, the researchers focused on the method of improving the saturation magnetic induction of amorphous materials, and carried out the system component research and strip performance evaluation. However, no one has done in-depth research on solving the problem of smoothing, lowering the composition of high-saturated amorphous materials, core processing, and transformer integration, and only recognizes the combination of necessary performances that are superior in core manufacturing and operation, so it was found A variety of different alloys, but each alloy is only part of this total combination. However, the preparation of amorphous alloy is a parameter of the saturation magnetic density, crystallization temperature, Curie temperature, monolithic loss, excitation power and other parameters, combined with the smoothness of the tape, material cost, process complexity, and the relatively high working magnetic force obtained. Multi-dimensional combination of dense, wide annealing interval, high ductility, low loss and low excitation power.

Summary of the invention

The technical problem to be solved by the present invention is to provide an iron-based amorphous alloy. The iron-based amorphous alloy provided by the present application has a high working magnetic density, a wide annealing interval, high ductility, low loss, and low excitation power.

In view of this, the present application provides an iron-based amorphous alloy as shown in formula (I).

Fe _a B _b Si _c (I);

Wherein, a, b and c respectively represent the atomic percentage of the corresponding component; 80.0 ≤ a ≤ 82.0, 11.0 ≤ b ≤ 13.0, 6.5 < c ≤ 8.0, a + b + c = 100.

Preferably, the iron-based amorphous alloy has a saturation magnetic induction of ≥1.60T.

Preferably, the atomic percentage of the Fe is 80.0 ≤ a ≤ 81.0.

Preferably, the atomic percentage of the B is 11.5 ≤ b ≤ 12.5.

Preferably, the atomic percentage of the Si is 7.0 ≤ b ≤ 7.5.

Preferably, in the iron-based amorphous alloy, a = 80.0, 12.0 ≤ b ≤ 13.0, and 7.0 ≤ c ≤ 8.0.

Preferably, in the iron-based amorphous alloy, a = 80.5, 11.5 ≤ b ≤ 12.5, and 7.0 ≤ c ≤ 8.0.

Preferably, in the iron-based amorphous alloy, 81.0 ≤ a ≤ 81.5, 11.0 ≤ b ≤ 13.0, 7.0 ≤ c ≤ 8.0.

The application also provides a preparation method of the iron-based amorphous alloy, comprising:

According to the atomic percentage of the iron-based amorphous alloy of the formula Fe _a B _b Si _c , the raw material after the compounding is melted, and the melted molten metal is heated and kept warm, and then subjected to single-roll quenching to obtain an iron-based amorphous alloy.

Preferably, after the single-roll quenching, the method further comprises:

The obtained iron-based amorphous alloy is subjected to heat treatment.

Preferably, the heat treatment temperature is 335 to 385 ° C, and the heat treatment has a wide interval of not less than 40 ° C.

Preferably, the heat-treated iron-based amorphous alloy strip has a coercive force of ≤3.5 A/m; at 50 Hz, 1.35 T, the heat-excited iron-based amorphous alloy has an excitation power of <0.1450 VA/ Kg, core loss <0.1100 W/kg; at 50 Hz, 1.40 T, the heat-treated iron-based amorphous alloy has an excitation power of <0.1700 VA/kg and a core loss of <0.1500 W/kg.

Preferably, the iron-based amorphous alloy strip is in a completely amorphous state with a critical thickness of at least 75 μm.

Preferably, the iron-based amorphous alloy ribbon has a thickness of 23 to 32 μm and a width of 100 to 300 mm.

The present application provides an iron-based amorphous alloy having an atomic composition of the formula Fe _a B _b Si _c , wherein a, b and c respectively represent the atomic content of the corresponding component; 80.0 ≤ a ≤ 82.0, 11.0 ≤ B≤13.0, 6.5<c≤8.0, a+b+c=100; Fe in the iron-based amorphous alloy provided by the present application can ensure stable amorphous iron base with lower preparation performance and higher band formation rate. Alloy; Si element is favorable for stable formation of amorphous material, suitable Si range can effectively reduce loss and ensure good toughness of quenched amorphous; B is the element that contributes the most to alloy amorphous state. The B content is insufficient, and the thermal stability of the obtained amorphous alloy ribbon is lowered. The present application has high saturation magnetic induction and high ductility by adjusting the contents of Fe, Si and B; meanwhile, the iron-based amorphous alloy of the present application has low loss and low excitation power in a wide annealing interval.

detailed description

The present invention has been described in detail with reference to the preferred embodiments of the present invention.

The embodiment of the invention discloses an iron-based amorphous alloy as shown in formula (I),

Fe _a B _b Si _c (I);

Wherein, a, b and c respectively represent the atomic content of the corresponding component; 80.0 ≤ a ≤ 82.0, 11.0 ≤ b ≤ 13.0, 6.5 < c ≤ 8.0, a + b + c = 100.

In the iron-based amorphous alloy provided by the present application, the content of Fe is 80.0 ≤ a ≤ 82.0 in terms of atomic percentage, If the content is less than 80%, the saturation magnetic induction density of the iron-based amorphous alloy is too low, which does not improve the defects of ordinary amorphous low magnetic density, and cannot obtain sufficient magnetic flux density and structurally dense core design, and the content is greater than 82.0. % reduces the thermal stability of the iron-based amorphous alloy and the formability of the strip, which makes the strip going straight and becomes difficult, and a good magnetic product cannot be obtained. In a specific embodiment, the atomic percentage of Fe may be 80.0%, 80.5%, 81.0%, or 81.5%.

The content of Si is 6.5<c≤8.0, and the content thereof is less than 6.5%, which reduces the formability of the strip and the thermal stability of the amorphous alloy strip, making it difficult to form an amorphous material stably; its content is higher than 8.0. %, the brittleness of the amorphous material is increased, and the ductility of the strip after annealing is deteriorated. In a specific embodiment, the Si content is 8.0%, 7.5%, or 7.0%.

The content of B is 11.0 ≤ b ≤ 13.0, and the content thereof is less than 11.0%, which makes it difficult to form an amorphous material stably, and more than 13% does not further increase the ability to form an amorphous state, that is, the above range The B content allows the amorphous iron-based alloy of the present invention to have excellent soft magnetic properties. In a particular embodiment, the B is present in an amount of 11.5%, 11.0%, 12.0%, 12.5%, or 13.0%.

More specifically, in certain embodiments, in the iron-based amorphous alloy, a = 80.0, 12.0 ≤ b ≤ 13.0, 7.0 ≤ c ≤ 8.0; in some embodiments, a of an iron-based amorphous alloy = 80.5, 11.5 ≤ b ≤ 12.5, 7.0 ≤ c ≤ 8.0; in some embodiments, the iron-based amorphous alloy has 81.0 ≤ a ≤ 81.5, 11.0 ≤ b ≤ 13.0, 7.0 ≤ c ≤ 8.0.

Therefore, the composition and content of the iron-based amorphous alloy of the present application form an iron-based amorphous alloy with high saturation magnetic induction strength from a reasonable combination of improving magnetic induction strength, improving amorphous forming ability, and reducing preparation difficulty.

The present application also provides a method for preparing the above iron-based amorphous alloy, comprising the following steps:

According to the atomic percentage of the iron-based amorphous alloy of the formula Fe _a B _b Si _c , the raw material after the compounding is smelted, and the melted molten metal is heated and maintained, and then quenched by a single roll to obtain an iron-based amorphous alloy strip. .

In the process of preparing an iron-based amorphous alloy, the present application employs the technical means conventional in the art to prepare an iron-based amorphous alloy of the specific composition of the present application. For the preparation process thereof regarding the process of compounding and smelting, the specific operation means of the present application are not specifically described. In the smelting process, the metal raw material is smelted using an intermediate frequency smelting furnace, the smelting temperature is 1300 to 1500 ° C, and the time is 80 to 120 min. After the smelting, in the present application, the melted molten metal is heated and maintained, and then subjected to single-roll quenching to obtain an iron-based amorphous alloy strip. The temperature of the temperature rise is preferably 1350 to 1470 ° C, and the time of the heat preservation is preferably 20 to 50 minutes. After a single roll quenching, the present application obtains an iron-based amorphous alloy strip which is completely amorphous, and has an amorphous limit band thickness of at least 75 μm, and the strip toughness is good, and the sheet is folded 180 degrees continuously. For the purpose of the present invention, the shear limit band thickness is at least 29 μm, which has a considerable preparation margin for the industrial production of the product, and reduces the requirements for the cooling equipment in the industrialization process thereof.

After the primary preparation of the amorphous iron-based alloy, the heat treatment of the amorphous iron-based alloy provided by the present application enables the amorphous iron-based alloy to be realized in a wide annealing range. The heat treatment and the resulting amorphous iron-based alloy strip have lower excitation power and loss. The heat treatment temperature in the present application is 325 to 395 ° C, and the heat treatment has a wide interval of not less than 40 ° C; in a specific embodiment, the heat treatment temperature is 335 to 385 ° C.

In order to further understand the present invention, the iron-based amorphous alloy provided by the present invention will be described in detail below with reference to the examples, and the scope of the present invention is not limited by the following examples.

According to the alloy composition represented by Fe _a B _b Si _c , the alloy composition shown in Table 1 is prepared using industrial pure iron, silicon or boron iron; the alloy component has inevitable impurity elements such as C in addition to the main element. , Mn, S, etc. The materials of different components are sequentially added to the intermediate frequency induction smelting furnace with a furnace capacity of 100kg in the order of boron iron, silicon and pure iron (the melting temperature is 1300-1500 ° C, the time is 80-120 min); the molten steel is calmed. At the end, it is poured into the spray bag, and an amorphous ribbon with an amorphous bandwidth of 20 mm is prepared by a single roll planar casting method. During the tape making process, alloy strips with different thicknesses are prepared by adjusting parameters such as roll speed and liquid level ( The roller speed during the belt making process is 1000 to 1400 r/min, and the belt speed is controlled to be 20 to 30 m/s, and the liquid level is 200 to 300 mm.

XRD was used to test the free surface of the different component strips until the strip was thick to amorphous. Table 1 shows the amorphous limit band thickness of each alloy component. The saturation magnetization values of each amorphous alloy strip were tested using VSM. The alloy composition was comprehensively evaluated by the strip amorphous forming ability and the saturation magnetic induction value. The maximum thickness of the strip can be determined according to the number of brittle points of the strip. The brittle point is evaluated by taking the length of the strip as the circumference of the crystallizer and cutting the strip along the length of the strip. The number of brittle points is not more than 2 The material can be sheared, and equal to 2 is considered to be the limit of the strip of the alloy component.

Table 1 Amorphous iron-based alloys with different compositions and their performance data sheets

Table 1 presents the different alloy compositions with corresponding amorphous limit band thickness, tape toughness limit band thickness, and saturation magnetic induction. The amorphous limit band thickness and the toughness limit of the tape are the considerations for the processability of the alloy component. The thicker the above tape, the more stringent the requirements for the tape making equipment.

Under the same conditions, the amorphous limit band thickness of the alloy composition is thicker, and the amorphous degree of the strip is higher. Although Comparative Examples 1 to 4 have a relatively high amorphous limit band thickness, the maximum shearable thickness is 27 μm or less, which not only imposes more stringent requirements on the cooling strength of the belt making equipment, but also on the assembly efficiency of the core, and at the same time on the transformer. During assembly and operation, easy debris has buried the foreshadowing, which has increased the safety hazard of transformer operation. In addition, its saturation magnetic density is less than 1.57T, which makes the design of amorphous transformer narrow and narrow, which can not meet the design trend of high magnetic density of transformer. Comparing Comparative Example 6 with Examples 4 to 6, it can be seen that the same Fe content, the higher the Si content, the smaller the shear thickness.

Comparative Example 8～9 alloy amorphous saturation magnetic density is obviously high. This is expected by transformer design. The maximum shearable thickness is between 36 and 38μm. It has absolute advantage in iron core forming efficiency, but its amorphous limit band It can be seen from the thickness value that the amorphous forming ability is obviously insufficient, and the process conditions of the slanting line are not obtained, and the excitation power and loss are also affected.

It can be seen from Table 1 that the alloy compositions of Examples 1 to 11 have a good process directivity and a wide transformer design interval from the consideration of tape straightening and transformer design.

The strips with the thickness of 26 to 28 μm in Table 1 were wound into a sample ring with an inner diameter of 50.5 mm and an outer diameter of 53.5 to 54 mm. The sample ring was subjected to stress relief annealing and annealing selection using a box annealing furnace. It was carried out in an argon-protected atmosphere, between 325 and 395 ° C, at intervals of 10 ° C, for 1 h. The heat treatment process adds a magnetic field along the strip preparation direction with a magnetic field strength of 1200 A/m. The silicon steel tester was used to test the excitation and loss of the strip after heat treatment. The test conditions were 1.35T/50Hz and 1.40T/50Hz, respectively. The performance test results are shown in Table 2:

Table 2 Performance data of the examples and comparative examples after heat treatment

It can be seen from Table 2 that under the condition of 1.35T/50Hz, the loss values of Comparative Examples 1 to 3 and Comparative Examples 8 to 9 are too large, and the performance is above 0.12 W/kg; and under the condition of 1.4 T/50 Hz, Comparative Example 1 The excitation and loss of ~4 and 6 are significantly higher than 1.35T/50Hz, and are significantly larger than other samples at 1.4T/50Hz, which is mainly related to the low saturation magnetic density of the above samples. The excitation and loss of amorphous materials increase with the increase of magnetic density, especially the performance of excitation power. An amorphous material with a large saturation magnetic induction strength has a lower saturation magnetic induction material, which allows a larger working magnetic density, that is, operation at a 1.4T magnetic density exhibits relatively low excitation power and loss. Normally, Comparative Examples 8-9 are tested at 1.4T, and the performance will be better. However, because of its large performance at 1.35T, the 1.4T loss and excitation increase, resulting in a large performance at 1.4T.

Examples 1 to 11 exhibited excellent soft magnetic properties at 1.35/50 Hz and 1.450/5 Hz; the 1.35/50 Hz loss was within 0.11 W/kg, and the 1.4 T/50 Hz loss was within 0.15 W/kg.

Amorphous materials have relatively low loss values. It is well known that by increasing the longitudinal magnetic field to remove stress during the preparation of the strip, each component can have an optimum heat treatment temperature value that achieves its optimum performance. In general, the annealing process can eliminate the stress of the amorphous magnetic material, reduce the coercive force, increase the magnetic permeability, and obtain excellent magnetic properties. Whether the heat treatment process control is reasonable is the key link to ensure the performance of the core. Due to its large volume, the amorphous iron core requires a slow heating rate or a longer holding time if the uniformity of the heat treatment temperature of the entire core is achieved, which is unsuitable for the final performance of the core. Based on the above research, a Fe _a B _b Si _c alloy-based amorphous alloy ribbon was invented, which had good magnetic properties even when temperature differences occurred in different portions of the core during annealing.

In this embodiment, the optimal heat treatment temperature range is increased to a wider range by limiting the range of components, and the iron core heat treatment can obtain iron with excellent performance in a wider heat treatment interval. Core data. The heat treatment temperature required is 325-395 ° C, the holding time is 60-120 min, and the magnetic field strength is 800-1400 A/m.

Table 3 different heat treatment temperature loss performance data sheet

Table 3 Table of different heat treatment temperature loss performance data (continued)

Table 4 Different heat treatment temperature excitation power performance data sheet

Table 4 Data Table of Excitation Power Performance of Different Heat Treatment Temperatures (Continued)

Table 3 and Table 4 are the data of loss and excitation values at different heat treatment temperatures. It can be seen from the table that the overall standard deviation of the loss in the example is within 0.017 within the heat treatment temperature range of 325-395, and the comparative example is above 0.020; The excitation power is within 0.040, the comparative ratio is above 0.05, and the comparative example 3 is significantly larger, with a deviation of 0.117, indicating that the heat treatment performance fluctuates greatly.

A certain deviation value is specified as a standard for evaluating the generality of heat treatment. In this experiment, the standard deviation of the specification is set within 0.01; according to the embodiment of the standard, the heat treatment and the loss heat treatment have a wide interval of 40 ° C or more, and the proportional loss has a wide interval of 30 °. At 40 ° C, the excitation wide interval is only 20 ° C, considering the excitation and loss, the ratio of the broad range is 20 ° C. In summary, the examples are wider than the comparative heat treatment by a wide interval of 20 ° C, allowing for wider heat treatment temperature fluctuations.

The above description of the embodiments is merely to assist in understanding the method of the present invention and its core idea. It should be noted that those skilled in the art can make various modifications and changes to the present invention without departing from the spirit and scope of the invention.

The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments are obvious to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but the scope of the invention is to be accorded

Claims (14)

1. An iron-based amorphous alloy as shown in formula (I),

   Fe _a B _b Si _c (I);

   Wherein, a, b and c respectively represent the atomic percentage of the corresponding component; 80.0 ≤ a ≤ 82.0, 11.0 ≤ b ≤ 13.0, 6.5 < c ≤ 8.0, a + b + c = 100.
2. The iron-based amorphous alloy according to claim 1, wherein the iron-based amorphous alloy has a saturation magnetic induction of ≥1.60T.
3. The iron-based amorphous alloy according to claim 1, wherein the atomic percentage of Fe is 80.0 ≤ a ≤ 81.0.
4. The iron-based amorphous alloy according to claim 1, wherein said B has an atomic percentage of 11.5 ≤ b ≤ 12.5.
5. The iron-based amorphous alloy according to claim 1, wherein said Si has an atomic percentage of 7.0 ≤ b ≤ 7.5.
6. The iron-based amorphous alloy according to claim 1, wherein in the iron-based amorphous alloy, a = 80.0, 12.0 ≤ b ≤ 13.0, and 7.0 ≤ c ≤ 8.0.
7. The iron-based amorphous alloy according to claim 1, wherein in the iron-based amorphous alloy, a = 80.5, 11.5 ≤ b ≤ 12.5, and 7.0 ≤ c ≤ 8.0.
8. The iron-based amorphous alloy according to claim 1, wherein in the iron-based amorphous alloy, 81.0 ≤ a ≤ 81.5, 11.0 ≤ b ≤ 13.0, and 7.0 ≤ c ≤ 8.0.
9. A method of preparing an iron-based amorphous alloy according to claim 1, comprising:

   According to the atomic percentage of the iron-based amorphous alloy of the formula Fe _a B _b Si _c , the raw material after the compounding is melted, and the melted molten metal is heated and kept warm, and then subjected to single-roll quenching to obtain an iron-based amorphous alloy.
10. The preparation method according to claim 9, wherein the single-roll quenching further comprises:

    The obtained iron-based amorphous alloy is subjected to heat treatment.
11. The production method according to claim 10, wherein the heat treatment temperature is 335 to 385 ° C, and the heat treatment has a wide interval of not lower than 40 ° C.
12. The preparation method according to claim 11, wherein the iron after the heat treatment The coercive force of the base amorphous alloy strip is ≤3.5A/m; at 50Hz, 1.35T, the excitation power of the heat-treated iron-based amorphous alloy is <0.1450VA/kg, and the core loss is <0.1100W/ Kg; at 50 Hz, 1.40T, the heat-treated iron-based amorphous alloy has an excitation power of <0.1700 VA/kg and a core loss of <0.1500 W/kg.
13. The preparation method according to claim 10 or 11, wherein the iron-based amorphous alloy ribbon is in a completely amorphous state and has a critical thickness of at least 75 μm.
14. The production method according to claim 10 or 11, wherein the iron-based amorphous alloy ribbon has a thickness of 23 to 32 μm and a width of 100 to 300 mm.